1. Field of the Invention
The present invention relates to it device for the intermediate storage of photographic sheet material with an entrance for receiving the material, an exit for discharging the material, several rotatably supported rollers for transporting the material in sheet form from the entrance to the exit and a drive means for driving the rollers.
2. Description of the Related Art
The devices this type can preferably be used in a so-called minilab. In the minilab, image originals recorded on photographic film are read with the device and the obtained image information is exposed on photographic sheet material in either analog or digital form. After the exposure step, the photographic sheet material is transferred to another station for developing the exposed photographic paper. The exposed image information which is recorded as a latent image of the photographic sheet, is thereby made visible and stabilized. Fully processed paper copies with the image information are returned at the exit of the minilab. The minilab performs the exposure end developing processes automatically in sequence. Disadvantageously, however, the exposure process may occur much faster than the developing process in which the photographic sheet paper passes through chemical baths which takes time. Since the image information of a following film is read only after the photographic paper associated with the current film has been fully exposed and developed, there may be a waiting time until the next film can be processed. This reduces the efficiency of the minilab.
It was therefore proposed in the U.S. Pat. No. 4,866,47220 to arrange between the station exposing the photographic paper and the station developing the photographic paper a device for intermediate storage of the exposed photographic paper. According to U.S. Pat. No. 4,866,472, a container is placed between the exposure station and the developing station, in which container the exposed photographic sheet paper is inserted at an entrance disposed at the top of the container. An exit is provided at the underside of the container, wherein the exposed photographic paper intermediately stored in the container is transferred to the developing station over a roller. The different sheets of the photographic paper are arranged in the container in the form of stacks. With his arrangement, the sheets can be supplied and withdrawn consecutively. The sheets are processed in the exposure and developing station in the original order. Since the exposed photographic paper is stacked in the container one on top of the other and adjacent sheets make contact which each other, this conventional device may disadvantageously cause adjacent sheets to damage each other. For example, the sheets can stick to one another.
The European patent application EP 0 708 365 A1 discloses a device for the intermediate storage of photographic sheet material which obviates the aforedescribed disadvantages. In the device disclosed in this reference, the photographic sheet paper is inserted into the intermediate storage device after exposure in the exposure station and transported onward through the intermediate storage device towards the entrance of the developing station. This prevents individual sheets of photographic paper from coming into contact with each other in the intermediate storage device. Different arrangements are proposed for receiving and transporting the individual sheets in the intermediate storage device. All these arrangements have in common that the sheets are transported by a band which moves over drive rollers. The transport speed of the sheets transported through the intermediate storage device is thereby held constant. To ensure that the disclosed intermediate storage device has sufficient storage capacity for the intermediate storage of photographic sheet paper and that the transit time of a sheet to be intermediately stored is kept as short as possible, it is proposed to make the transport path of the sheets through the intermediate storage device dependent on the total number of sheets held in the intermediate storage device. Mechanical assemblies which can be used to vary the transport path of the intermediate storage device--and thereby also the storage capacity of the intermediate storage device--tend to be quite complex.